F:Flammable;1634-04-4Relevant articles and documents
Heteropoly Acids Supported on Acidic Ion-exchange Resin as Highly Active Solid-acid Catalysts
Baba, Toshihide,Ono, Yoshio,Ishimoto, Tadao,Moritaka, Shun-ichi,Tanooka, Seiichi
, p. 2155 - 2156 (1985)
Heteropoly acids supported on a macroreticular acidic ion-exchange resin shows much higher activity than those supported on activated carbon for the synthesis of methyl t-butyl ether and the esterification of acetic acid with 1-pentanol.This high activity can plausibly be attributed to the interaction of heteropoly anions with substrates which are protonated by the protons of the acidic resin.
Hopper,S.P. et al.
, p. 331 - 340 (1978)
High-pressure heat-flow calorimeter. Determination of the enthalpy of reaction for the synthesis of methyl t-butyl ether from methanol and 2-methylpropene
Arntz, H.,Gottlieb, K.
, p. 967 - 972 (1985)
A high-pressure heat-flow calorimeter suitable for measuring enthalpies of reaction and heat capacities is described.With the calorimeter, thermodynamic properties can be studied from 290 to 600 K and from 0.1 to 10 MPa.The reaction enthalpy for the synthesis of methyl t-butyl ether from methanol and 2-methylpropene using an acidic ion-exchange-resin catalyst was measured at 319 K and 1.6 MPa.The molar reaction enthalpy is given by ΔrHm(319 K, 1.6 MPa) = -(39.8 +/- 0.4)kJ.mol-1.The corresponding standard molar enthalpy of formation of methyl t-butyl ether is ΔfHm0(l, 298.15 K) = -315.4 kJ.mol-1.
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Barton,D.H.R. et al.
, p. 1466 (1970)
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On Anchimerically Assisted Homolysis via Sulphide Functions
Lawson, Alexander J.
, p. 1238 - 1239 (1981)
In contrast to O-O fission, anchimeric assistance from sulphide functions in the rate of unimolecular fission of the N-O bond is only marked for heterolysis reactions; analogous homolyses are very much less accelerated, although bridged radical intermediates are involved.
Kinetics of liquid phase synthesis of methyl tert-butyl ether from tert-butyl alcohol and methanol catalyzed by ion exchange resin
Matouq,Goto
, p. 825 - 831 (1993)
Synthesis of methyl tert-butyl ether (abbreviated as MTBE) from methanol (MeOH) and tert-butyl alcohol (TBA) in the liquid phase was studied by using Amberlyst 15 in the H+ form as an acid catalyst. Experiments were carried out in a stirred batch reactor at different temperatures (313, 318, and 323 K) under atmospheric pressure. It was found that catalyst sizes and rotation speeds had no significant effects on reaction rates. Mechanism studies showed that three reactions took place simultaneously. It was also found that dehydration of TBA could not be neglected. The experimental concentration profiles with time could be simulated well by simple kinetics. Finally, rate constants could be expressed by Arrhenius equations.
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Saenger,v. Sonntag
, p. 5489,5501 (1970)
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Catalysis in a porous molecular capsule: Activation by regulated access to sixty metal centers spanning a truncated icosahedron
Kopilevich, Sivil,Gil, Adria,Garcia-Rates, Miquel,Bonet-Avalos, Josep,Bo, Carles,Mueller, Achim,Weinstock, Ira A.
, p. 13082 - 13088 (2012)
The 30 cationic {MoV2O4(acetate)} + units linking 12 negatively charged pentagonal "ligands," {(MoVI)MoVI5O21(H 2O)6}6- of the porous metal-oxide capsule, [{MoVI6O21(H2O)6} 12{MoV2O4(acetate)} 30]42- provide active sites for catalytic transformations of organic "guests". This is demonstrated using a well-behaved model reaction, the fully reversible cleavage and formation of methyl tert-butyl ether (MTBE) under mild conditions in water. Five independent lines of evidence demonstrate that reactions of the MTBE guests occur in the ca. 6 × 10 3 A3 interior of the spherical capsule. The Mo atoms of the {MoV2O4(acetate)}+ linkers - spanning an ca. 3-nm truncated icosahedron - are sterically accessible to substrate, and controlled removal of their internally bound acetate ligands generates catalytically active {MoV2O4(H 2O)2}2+ units with labile water ligands, and Lewis- and Bronsted-acid properties. The activity of these units is demonstrating by kinetic data that reveal a first-order dependence of MTBE cleavage rates on the number of acetate-free {MoV2O 4(H2O)2}2+ linkers. DFT calculations point to a pathway involving both Mo(V) centers, and the intermediacy of isobutene in both forward and reverse reactions. A plausible catalytic cycle - satisfying microscopic reversibility - is supported by activation parameters for MTBE cleavage, deuterium and oxygen-18 labeling studies, and by reactions of deliberately added isobutene and of a water-soluble isobutene analog. More generally, pore-restricted encapsulation, ligand-regulated access to multiple structurally integral metal-centers, and options for modifying the microenvironment within this new type of nanoreactor, suggest numerous additional transformations of organic substrates by this and related molybdenum-oxide based capsules.
Coadsorption of methanol and isobutene on HY zeolite
Kogelbauer,Goodwin,Lercher
, p. 8777 - 8781 (1995)
In order to develop a better understanding of methyl tert-butyl ether (MTBE) synthesis on zeolites, the coadsorption of methanol and isobutene on HY zeolite was investigated using IR spectroscopy. Initial adsorption of isobutene alone at 35°C led to rapid oligomerization yielding strongly bound oligomers. The subsequent coadsorption of methanol did not induce any changes in the zeolite-adsorbate complexes. TPD following the coadsorption showed that the Bronsted acid sites could be restored by temperature treatment above approximately 300°C. When methanol was adsorbed first and isobutene was subsequently coadsorbed, MTBE was formed even at 35°C on the catalyst surface. MTBE desorbed easily at a temperature of 70°C, restoring a major fraction of the Brosted acid sites. Methanol was concluded to decrease the probability of oligomerization by effectively competing for the acid sites.
Liquid phase synthesis of MTBE from methanol and isobutene over acid zeolites and Amberlyst-15
Collignon,Loenders,Martens,Jacobs,Poncelet
, p. 302 - 312 (1999)
The liquid phase synthesis of methyl tert-butyl ether (MTBE) from methanol and isobutene over H-Beta and US-Y zeolite catalysts was studied in the temperature range 30-120°C. Up to 100°C, commercial H-Beta zeolite samples with small crystal size were more active than acid Amberlyst-15 (reference catalyst) and noticeably more active than US-Y, confirming results obtained under vapour phase conditions. The influence of methanol/isobutene (MeOH/IB) molar ratio, pressure, and space time on the conversion and MTBE selectivity was investigated. At optimized reaction conditions, MTBE yields of 85-90% can be reached with zeolite H-Beta as well as Amberlyst-15. On zeolites, side reactions of isobutene are more important than on Amberlyst-15, necessitating operation at MeOH/IB ratios higher than 1:1. For the same reason, at high conversion on H-Beta, the MTBE yields are more sensitive to contact time compared to Amberlyst-15. On H-Beta zeolite, no deactivation was observed during a period of more than 50 h on stream at 65°C, 1.4 MPa pressure, and a WHSV of 14 h-1. The catalytic activity of the zeolites is related to the external specific surface area, and to the concentration of bridging hydroxyls and silanol groups in the mesopores. A zeolite H-Beta sample with a Si/Al ratio of 36 has an optimum silanol and bridging hydroxyl content leading to stoichiometric methanol and isobutene adsorption, highest activity and MTBE yields.
Reactivity and Product Analysis of a Pair of Cumyloxyl and tert-Butoxyl Radicals Generated in Photolysis of tert-Butyl Cumyl Peroxide
Oyama, Ryoko,Abe, Manabu
, p. 8627 - 8638 (2020/07/21)
Alkoxyl radicals play important roles in various fields of chemistry. Understanding their reactivity is essential to applying their chemistry for industrial and biological purposes. Hydrogen-atom transfer and C-C β-scission reactions have been reported from alkoxyl radicals. The ratios of these two processes were investigated using cumyloxyl (CumO?) and tert-butoxyl radicals (t-BuO?), respectively. However, the products generated from the pair of radicals have not been investigated in detail. In this study, CumO? and t-BuO? were simultaneously generated from the photolysis of tert-butyl cumyl peroxide to understand the chemical behavior of the pair of radicals by analyzing the products and their distribution. Electron paramagnetic resonance and/or transient absorption spectroscopy analyses of radicals, including CumO? and t-BuO?, provide more information about the radicals generated during the photolysis of tert-butyl cumyl peroxide. Furthermore, the photoproducts of (3-(tert-butylperoxy)pentane-3-yl)benzene demonstrated that the ether products were formed in in-cage reactions. The triplet-sensitized reaction induced by acetophenone, which is produced from CumO?, clarified that the spin state did not affect the product distribution.
Methyl tert-butyl ether synthesis method
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Paragraph 0015, (2016/10/07)
The invention discloses a methyl tert-butyl ether synthesis method. The method comprises that according to a reaction mole ratio of 1: 1-4: 1, methanol and tert-butyl alcohol undergo a dehydration condensation reaction in the presence of an acidic catalyst and a dehydrant at a reaction temperature of 50-100 DEG C for 2-4h to produce a methyl tert-butyl ether crude product, and the crude product is purified through distillation to form high purity methyl tert-butyl ether. The synthesis method has mild conditions, can be operated simply, has economy and practicality and is suitable for large scale industrial production.
